Geology, Mode of Occurrences and X-Ray Diffraction Studies of Cretaceous Phosphatic Nodules, Nambakuruchi Block of Tiruchirappalli District, Tamil Nadu, India

Abstract

The Cretaceous phosphatic deposits of Tiruchirappalli district Tamil Nadu is one of the critical exposers in  the world. The present studies revealed that the geological set-up, mode of occurrence and mineralogical  character based on X-Ray diffraction studies. The basement of the Cretaceous phosphatic deposits is  Archean, which is overlain by the Upper Gondwana, followed by the Uttatur, Tiruchirappalli, Ariyalur,  Niniyur, Cuddalore, and Alluvium. The phosphatic deposits consist of the Uttatur Group in Karai  formation. The type of occurrence of the phosphate is in nodular form exposed on the land with  Maruvattur Clay or Karai Shale showing badland topography. The size of nodules varies from sizes 2 to 5  cm width and 6 – 20 cm length with different shapes like circular, cylindrical, conical, rectangular, and  elliptical. The surface colour is yellow to ferruginous. The XRD revealed that the CFA is the main  phosphate mineral and calcite, quartz, montmorillonite, and hematite are the gangue minerals present in  phosphatic nodules.